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Join Date: Feb 2009
Posts: 10

IS and NIS instruments

05/28/2010 6:03 PM

How will I know if an instrument is intrinsic safety (IS) or non-intrinsic safety (NIS). Will there be a specific list of instruments for IS and NIS?

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Guru

Join Date: Oct 2008
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#1

Re: IS and NIS instruments

05/28/2010 7:32 PM

You should go here:

Intrinsic safety - Wikipedia, the free encyclopedia

Then maybe give some idea of what you really want. A comprehensive list would be very large.

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Power-User

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Location: Mumbai
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#2

Re: IS and NIS instruments

05/31/2010 11:32 AM

You Can look at the Descripition to see whether it mentions Exia , which means the instrument Is intrinsically safe

Regards

Jose

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#5
In reply to #2

Re: IS and NIS instruments

08/09/2021 11:03 AM

...when installed and maintained correctly.

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Power-User

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#6
In reply to #5

Re: IS and NIS instruments

08/11/2021 5:40 PM

1. Intrinsically Safe instruments always have a control drawing that shows the approved field wiring with conditional requirements. Control drawings are usually included in the installation/operations manual but are sometimes separate documents published by the manufacturer.
Sample I/S control drawing:


2. The ID nameplate attached to the instrument generally includes the approval agency and the I/S categories for which the instrument was certified. Although sometimes that information is encoded in the model number.


Many I/S instruments do not actually differ from their non-I/S cousins, except for the model number that includes I/S certification and the appropriate notation on the instrument name plate, meaning that internally I/S and non-I/S are the same, however, one cannot make that assumption in the field. If the nameplate does not provide the I/S certification, then the instrument is not to be used in an I/S circuit.

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Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

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#3

Re: IS and NIS instruments

06/01/2010 4:37 AM

Intrinsic safety is a technique that involves reducing the voltage and current in the hazardous area below the point where an incendive spark can occur. Even though an instrument may be intrinsically safe, and the answer to its status can be found on its type test certificate and on a label permanently attached to it, whether the circuit is intrinsically safe with the instrument connected to it depends upon the correct selection of barrier device(s) and cable(s) as the other parts of the installation.

  1. Review the Wikipedia article on the topic.
  2. The design of circuits and the selection of equipment for use in hazardous areas requires a certain level of training. Request attendance on a training course.
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Member

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#4

Re: IS and NIS instruments

06/04/2010 7:28 AM

In addition to the previous stated ways, look at the cable. In some applications (Oil Field) Intrinsically Safe cable is light blue. But to be sure, look at the system specifications. In some cases (Nuclear Power Industry) there will be a list of intrinsically safe equipment, which will include instrumentation. I hope this helps.

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